Problem-Echo 2000/2-3

a) 1.Sf6-e4 Gc6-h6 2.c4-c3 Ng2-a5#
b) 1.c4-c3 Ng2-a5 2.Sf6-e4 Gc6-h6#

4; 6; (3); 5; 15

Motivation is analogical - in fact the same in both phases, forgetting about preventing of check to white king.

1...Gd6-h2 2.Ng3-e4 Sd3-f4#
1.Ng3-c5 Gd6-b4 2.Nc5-e4 Se6-f4#

5; 5; (2); 6; 16

If one places knight on e4, two solutions can be done without nightrider.

1.Bd3-f5 Nf8-b6 2.Ke5-e6 Nb6-d7#
1.Ge7-e4 Ga6-e6 2.Ke5-d4 Ge6-e3#

6; (3); 8; 5,5; 19,5

Very good reciprocal batteries, moves of black king allow more unified motivation in comparison with my problem from Problem-Echo 2000/2-1. The best of lighter problems.

1.Bb6-d4 Nf3-d2 2.Bh1-b7 Gc4-g8#
1.Rd6-d4 Nf3-h4 2.Bh1-a8 Gf5-f8#

7; 8; (3); 8,5; 23,5

Basic scheme with indirect batteries calls for better rendering - I was unable to find one...

a) 1.Se7-g6 Gd8-h4 2.Ke4-f3 Nb6-f4#
b) 1.Se7-g8 Gf7-b7 2.Ke4-d4 Nh3-d5#

(6); 10; 9; 9,5; 28,5

I found this excellent scheme during one very boring lecture on accounting... Almost ideal matching of strategy. The only drawback is that bS move once removes guard from mating line what is unmatched in the other phase. The mates with triple antibatteries (direct and double indirect) are perfectly suitable. Also the twinning was the lucky find.

a) 1.f5-f4 Nh8-f7 2.Gf6-f3 Ne2-c3#
b) 1.Ga1-a5 Nb3-c5 2.Ga5-d5 Nh8-f7#
c) 1.Ga1-g7 Ne2-c3 2.Gg7-e5 Nb3-c5#

(9,5); 9; 7,5; 7,5; 24

The use of grasshoppers isn't justified, the blocks could have been arranged the other way. Nightriders play well, model mates have unusual patterns.

a) 1.e2-e1=N Ne5-c1 2.Ne1-a3 Nc1-e2#
b) 1.e2-e1=G Gd2-h6 2.Ge1-a5 Gh6-c6#

7; 6; (3); 5; 18

I don't think there is any dual-avoidance here as black moves carry no effects causing the avoidance of dual continuations, the error always lies only in the wrong white moves. The given lines are simply tries. Fairy promotions.

1.Ga6-d3 Ng8-e7 2.Gd3-a3 Ne7-h1#
1.Na7-b5 Kf6-g5 2.Nb5-a3 Gd8-h4#

6,5; 6; 6,5; (5); 19

Reciprocal change of functions Gd8-Ng8 isn't complicated. Double-grasshopper-pin mates are interesting, but the pins are static.

a) 1.Gh8-a1 Nh7-f6 2.Ng2-d8 Nb2-d6#
b) 1.Ga2-a7 Nb2-d6 2.Gh8-a8 Nh7-f6#

5; (7); 5; 3,5; 13,5

White moves are obviously reverted by moving bK just 1 square, black moves are chosen in interesting although non-homogeneous manner.

1.Gc2-a4 Nd2-g8 2.Nf3-b5 Ge7-e5#
1.Nf3-b5 Nf4-g2 2.Gc2-a4 Ge3-a3#

8; 7; 7; (4); 22

Quite good geometry of white lines. Black play is boring. I don't think there is any dual avoidance in a) as move Gc6 is present already in diagram position. On the other hand, in b) black move Nb5 provides later Gc4 - this is dual avoidance.

a) 1.Bg1xe3 Na4xc5 2.Be3-f4 Nc4-e5#
b) 1.Ga2xc4 Na4-c8 2.Gc4-e6 Bd6-e5#
c) 1.Gd1xd6 Na4-b2 2.Gd6-g6 Re3-e5#

9; (8); 9,5; 9; 27,5

Funny is that the only positive motivation of black play is blocking on 2nd move. To reach that aim he must capture on of 3 thematical pieces that are cyclically changing their functions. Excellent base scheme, an idea genuinely using N&G combination. The only flaw - scheme is based on changing flights and 2nd mate isn't model. Pity.

a) 1.Qg8-e6 Nh1-d3 2.Ba8-d5 Nd3-f7#
b) 1.Ba8-c6 Nh5-d3 2.Qg8-d5 Nd3-b7#

5,5; 6; (4,5); 5,5; 17

I found the changes of flights' covering on 7th rank interesting, but the rest is completely symmetrical.